An image scanner refers to an image input device that optically scans various media, such as documents, drawings, photos, films, checks, securities and the like, and converts analog signals indicative of the intensity of reflected or transmitted light to digital signals to thereby input digital images. Generally, the image scanner is interfaced with a computer for processing image data.
U.S. Pat. No. 7,149,012 discloses an image scanner designed to scan the surfaces of a medium placed on a window glass by moving an image sensor, e.g., a charge-coupled device (CCD) or an amorphous semiconductor, across the medium. With this image scanner, however, a user has to turn up the medium and reload it on the window glass with the opposite side in order to scan the other surface of the medium. This task is quite onerous and time-consuming.
U.S. Patent Publication No. 2006/0256391A1 discloses a double side image scanner that scans both surfaces of a medium while causing a roll feeder to load the medium toward two image sensors mounted to the lateral sides of a guide track. Provision of the two image sensors on the lateral sides of the guide track leads to a complicated structure and a difficult fabrication process, which in turn reduces productivity and increases production costs.